Refactor overpass support using own implementation of overpass layer.

assets/osmtogeojson/parse_osmxml.js

@@ -0,0 +1,91 @@
+/* converts OSM XML to OSM JSON using a fast streaming parser */
+var htmlparser = require('htmlparser2');
+var _ = require("./lodash.custom.js");
+
+var json = {
+    "version": 0.6,
+    "elements": []
+};
+var buffer = {};
+var p = new htmlparser.Parser({
+    onopentag: function(name, attr) {
+        switch (name) {
+        case "node":
+        case "way":
+        case "relation":
+            buffer = {
+                type: name,
+                tags: {}
+            }
+            _.merge(buffer, attr);
+            if (name === "way") {
+                buffer.nodes = [];
+                buffer.geometry = [];
+            }
+            if (name === "relation") {
+                buffer.members = [];
+                buffer.nodes = [];
+                buffer.geometry = [];
+            }
+        break;
+        case "tag":
+            buffer.tags[attr.k] = attr.v;
+        break;
+        case "nd":
+            buffer.nodes.push(attr.ref);
+            if (attr.lat) {
+                buffer.geometry.push({
+                    lat: attr.lat,
+                    lon: attr.lon
+                });
+            } else {
+                buffer.geometry.push(null);
+            }
+        break;
+        case "member":
+            buffer.members.push(attr);
+        break;
+        case "center":
+            buffer.center = {
+                lat: attr.lat,
+                lon: attr.lon
+            };
+        break;
+        case "bounds":
+            buffer.bounds = {
+                minlat: attr.minlat,
+                minlon: attr.minlon,
+                maxlat: attr.maxlat,
+                maxlon: attr.maxlon
+            };
+        }
+    },
+    ontext: function(text) {
+    },
+    onclosetag: function(name) {
+        if (name === "node" || name === "way" || name === "relation" || name === "area") {
+            // remove empty geometry or nodes arrays
+            if (buffer.geometry && buffer.geometry.every(function(g) {return g===null;}))
+                delete buffer.geometry;
+            if (name === "relation")
+                delete buffer.nodes;
+            json.elements.push(buffer);
+        }
+        if (name === "member") {
+            if (buffer.geometry) {
+                buffer.members[buffer.members.length-1].geometry = buffer.geometry;
+                buffer.geometry = [];
+            }
+        }
+    }
+}, {
+    decodeEntities: true,
+    xmlMode: true
+});
+
+p.parseFromString = function(xml_str) { p.write(xml_str); p.end(); return json; }
+p.getJSON = function() {
+    return json;
+}
+
+module.exports = p;